This yearning love song is the lead single from In the Lonely Hour. It was released in the UK on February 15, 2013. The song entered the British singles chart at #46 after being referenced by host James Corden at the 2014 BRIT Awards.

Smith explained to MTV News how this was the song that kick-started his music career. "Disclosure heard 'Lay Me Down,' and [after that] it was like a domino effect," he said. "We wrote 'Latch' together, and then Naughty Boy heard 'Latch' and we wrote 'La La La' together, and then I had a number-one single in the UK."

The song was written by Sam Smith with Jimmy Napes, who helped write Disclosure's hits "Latch," "White Noise" and "You & Me." and newcomer Elvin Smith. The Disclosure pair produced the tune.

Smith performed the song along with "Stay With Me" during his debut appearance on the March 29, 2014 episode of Saturday Night Live.

The song secured Smith a record deal. London Records' Nick Raphael recalled to Billboard magazine: "I remember hearing 'Latch' and thinking, 'No person can go through that many vocal ranges at one time without going through a computer. And then he played 'Lay Me Down,' and I remember getting in the car afterward, calling the business affairs guy and saying, 'Whatever we do, we must close this deal.'"

Sam Smith went back into the studio in January 2015 to re-record the tune for its single release. The new version of the song was done with its original producers Jimmy Napes and Steve Fitzmaurice.

The music video was directed by Ryan Hope, whose other clients include George Michael ("White Light"), 2 Chainz ("Feds Watching") and Wiz Khalifa ("Remember You"). The clip was filmed in a South East London church and starts with a funeral before turning into a wedding scene, with Smith exchanging vows with his male partner. The singer said: "With this video myself and Ryan Hope the director have decided to make a statement and showcase something we passionately believe in."

"This video shows my dreams that one day gay men and women and transgendered men and women all over the world, like all our straight families and friends, will be able to get married under any roof, in any city, in any town, in any village, in any country."

Sam Smith partnered with John Legend to record a new version of the song for Comic Relief. The special track was released on March 9, 2015, with all proceeds going to the UK charity.

The collaboration with John Legend topped the UK singles charts. It was Smith's fourth #1 in his home country, following the singer's guesting on Naughty Boy's "La La La" and his own "Money On My Mind" and "Stay With Me."

Much of In the Lonely Hour deals with a case of unrequited love Smith suffered when he fell for a guy who turned out to be straight, and thus not interested in his advances. The singer explained during his gig at the O2 Academy in Brixton, London that he wrote "Lay Me Down" after deleting the unresponsive guy from his WhatsApp account.